alpha-MSH comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2025-12-12. Where a claim depends on a specific study, the study is described rather than over-claimed.
Research interest has centred on photoprotection and pigmentation, with a smaller body of work on appetite and sexual function. Published human data remain limited to small, frequently uncontrolled studies, and the compound has never received marketing approval from a national medicines regulator. Most laboratory work treats it as a pharmacological tool for probing melanocortin signalling in cell culture or animal models. Whether pigmentation changes observed in people translate into measurable protection against ultraviolet-induced DNA damage remains an open question.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, the naturally occurring peptide involved in pigmentation signalling. Its sequence is conventionally written as Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, with a lactam bridge joining the aspartate side chain to the lysine side chain. The empirical formula is C50H69N15O9 and the monoisotopic mass lies near 1023.5 daltons. N-terminal acetylation and the D-configured phenylalanine both increase resistance to enzymatic breakdown compared with the parent hormone.
No regulatory authority has approved melanotan-2 for human use, and several countries classify it as a prescription-only or controlled substance, which restricts lawful supply. Material sold online is generally labelled as a research chemical and is not required to meet pharmaceutical standards of identity or purity. Published human data consist mainly of small uncontrolled studies, case reports and adverse-event notifications, so the evidence base is descriptive rather than confirmatory. Whether repeated melanocyte stimulation alters long-term naevus behaviour remains an open question that no completed trial has resolved.
Melanotan-2 is a synthetic cyclic heptapeptide designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous tridecapeptide that regulates pigment production. Two modifications distinguish it from the natural hormone: norleucine replaces methionine at the N-terminus, which limits oxidation, and a D-phenylalanine substitution raises receptor affinity. The ring is closed through an aspartate-lysine lactam bridge, giving the molecule a constrained conformation. The free base has a molecular mass near 1024 daltons, and commercial material is usually supplied as an acetate salt. It appears in the literature as a research peptide rather than an approved therapeutic agent.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Melanotan II; MT-II; N-acetyl-norleucyl-cyclo[Asp-His-D-Phe-Arg-Trp-Lys] amide | Naming follows peptide convention; the numeral distinguishes it from melanotan-1 |
| Molecular formula | C50H69N15O9 | Includes the lactam bridge; no counter-ion assumed |
| Monoisotopic mass | 1023.53 Da | Free base; salts and counter-ions shift the observed value |
| Appearance | White to off-white lyophilised powder | Batch-to-batch colour variation is not itself proof of impurity |
| Typical analytical method | RP-HPLC purity determination with ESI-MS identity confirmation | Retention time alone does not establish sequence identity |
The compound emerged from research programs in the 1980s that examined analogues of alpha-melanocyte-stimulating hormone for pigmentation and photoprotection. Investigators modified the native sequence to extend activity duration and potency. A related analogue, afamelanotide, was developed within the same broad line of inquiry and eventually gained approval in certain jurisdictions for a rare light-sensitivity condition. Melanotan-2 itself did not progress through the same regulatory route and has no approved therapeutic indication.
Melanocortin receptors comprise five subtypes with distinct tissue distributions and functions. Melanotan-2 is described in the literature as a non-selective agonist that engages several of these subtypes, including MC1R, MC3R, MC4R, and MC5R. MC1R is the subtype most directly linked to melanin production in skin cells. Because the compound is not subtype-selective, its observed effects in experimental settings are generally attributed to activity across multiple receptor pathways rather than to a single target.
Melanotan-2 is a synthetic linear peptide built from seven amino acids arranged in a short chain. Its sequence is commonly written as Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-NH2, which includes a modified N-terminus and an amidated C-terminus. The molecule belongs to the melanocortin family and acts as a receptor agonist. Structural features such as the D-phenylalanine residue and the Nle substitution are associated with increased stability against enzymatic degradation relative to the natural parent peptide.
Acetyl-CoA carboxylase 1 (ACC1) Carbamoyl phosphate synthetase 1 (CPS1) Carnitine palmitoyltransferase 1 (CPT1) Enolase 1 (ENO1) Formyltetrahydrofolate dehydrogenase, 10- (ALDH1L1) Fructose bisphosphate aldolase B (ALDOB) Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) Histone H2B Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) Very long-chain acyl-CoA dehydrogenase (VLCAD)
Diagnosis is made on interview and physical examination. More than one finger may be affected at a time. Trigger Finger is most common in the thumb and ring finger. The triggering occurs when making a fist or while gripping an object firmly. Triggering can be more noticeable in the morning, presumably because the enlargement of the tendon is maximum when the finger is not being used. Upon waking, the affected person may have to force the triggered fingers open with their other hand. In some, this can be a daily occurrence.
Diagenesis () is the process of physical and chemical changes in sediments first caused by water-rock interactions, microbial activity, and compaction after their deposition. Increased pressure and temperature only start to play a role as sediments become buried much deeper in the Earth's crust. In the early stages, the transformation of poorly consolidated sediments into sedimentary rock (lithification) is simply accompanied by a reduction in porosity and water expulsion (clay sediments), while their main mineralogical assemblages remain unaltered. As the rock is carried deeper by further deposition above, its organic content is progressively transformed into kerogens and bitumens. The process of diagenesis excludes surface alteration (weathering) and deep metamorphism. There is no sharp boundary between diagenesis and metamorphism, but the latter occurs at higher temperatures and pressures. Hydrothermal solutions, meteoric groundwater, rock porosity, permeability, dissolution/precipitation reactions, and time are all influential factors. After deposition, sediments are compacted as they are buried beneath successive layers of sediment and cemented by minerals that precipitate from solution. Grains of sediment, rock fragments and fossils can be replaced by other minerals (e.g. calcite, siderite, pyrite or marcasite) during diagenesis. Porosity usually decreases during diagenesis, except in rare cases such as dissolution of minerals and dolomitization.
Diffuse scleroderma can affect any part of the gastrointestinal tract. The most common manifestation in the esophagus is reflux esophagitis, which may be complicated by esophageal strictures or benign narrowing of the esophagus. This is best initially treated with proton pump inhibitors for acid suppression, but may require bougie dilatation in the case of stricture. Scleroderma can decrease motility anywhere in the gastrointestinal tract. The most common source of decreased motility is the esophagus and the lower esophageal sphincter, leading to dysphagia and chest pain. As scleroderma progresses, esophageal involvement from abnormalities in decreased motility may worsen due to progressive fibrosis (scarring). If this is left untreated, acid from the stomach can back up into the esophagus, causing esophagitis and gastroesophageal reflux disease. Further scarring from acid damage to the lower esophagus many times leads to the development of fibrotic narrowing, also known as strictures, which can be treated by dilatation. In patients with neuromuscular disorders, particularly progressive systemic sclerosis and visceral myopathy, the duodenum is frequently involved. Dilatation may occur, which is often more pronounced in the second, third, and fourth parts. The dilated duodenum may be slow to empty, and the grossly dilated, atonic organ may produce a sump effect. The small intestine can also become involved, leading to bacterial overgrowth and malabsorption of bile salts, fats, carbohydrates, proteins, and vitamins.
==== Balancing infection and autoimmunity ==== There is increasing evidence that certain genes selected during evolution offer a balance between susceptibility to infection and the capacity to avoid autoimmune diseases. For example, variants in the ERAP2 gene provide some resistance to infection even though they increase the risk of autoimmunity (positive selection). In contrast, variants in the TYK2 gene protect against autoimmune diseases but increase the risk of infection (negative selection). This suggests the benefits of infection resistance may outweigh the risks of autoimmune diseases, particularly given the historically high risk of infection. Several experimental methods such as the genome-wide association studies have been used to identify genetic risk variants that may be responsible for diseases such as type 1 diabetes and rheumatoid arthritis.
Sources: en.wikipedia.org
== Amino acid degradation == Oxidative deamination is the first step to breaking down the amino acids so that they can be converted to sugars. The process begins by removing the amino group of the amino acids. The amino group becomes ammonium as it is lost and later undergoes the urea cycle to become urea, in the liver. It is then released into the blood stream, where it is transferred to the kidneys, which will secrete the urea as urine. The remaining portion of the amino acid becomes oxidized, resulting in an α-keto acid. The alpha-keto acid will then proceed into the TCA cycle, in order to produce energy. The acid can also enter glycolysis, where it will be eventually converted into pyruvate. The pyruvate is then converted into acetyl-CoA so that it can enter the TCA cycle and convert the original pyruvate molecules into ATP, or usable energy for the organism. Transamination leads to the same result as deamination: the remaining acid will undergo either glycolysis or the TCA cycle to produce energy that the organism's body will use for various purposes. This process transfers the amino group instead of losing the amino group to be converted into ammonium. The amino group is transferred to α-ketoglutarate, so that it can be converted to glutamate. Then glutamate transfers the amino group to oxaloacetate. This transfer is so that the oxaloacetate can be converted to aspartate or other amino acids.
Israeli airstrikes hit Iranian oil storage facilities, killing four people. Strikes on fuel depots near Tehran caused a "river of fire" to pour out along the streets, and the city became engulfed in thick black smoke, causing toxic acidic rain to fall in the surrounding area. US Central Command announced the death of a seventh US service member from an Iranian attack. The UK confirmed its forces had intercepted an Iranian drone headed towards Iraq, and declared its intention to send a Merlin helicopter to the region to detect aerial threats. According to the Iranian Red Crescent Society, 65 schools and 32 medical facilities had been targeted, and more than 10,000 civilian sites damaged. On 9 March, NATO confirmed the interception of a second ballistic missile in Turkish airspace. Turkey deployed six F-16s and air defense systems to Northern Cyprus. Trump claimed that "the war is very complete, pretty much", after speaking with Russian president Putin, and said "we already won the war in many ways." Following Syrian president Ahmed al-Sharaa's support for Lebanon's objective to disarm Hezbollah, the group targeted the city of Inkhil in Syria. About a dozen B-1B bombers arrived at bases in Europe.
Besides the environmental damage, the health of both local factory workers and the end consumer is also negatively affected. After approximately 15 years of ignoring high court rulings, the government shut down more than 100 tanneries the weekend of 8 April 2017 in the neighborhood. The higher cost associated with the treatment of effluents than to untreated effluent discharging leads to illegal dumping to save on costs. For instance, in Croatia in 2001, proper pollution abatement cost US$70–100 per ton of raw hides processed against $43/t for irresponsible behavior. In November 2009, one of Uganda's main leather making companies was caught directly dumping waste water into a wetland adjacent to Lake Victoria.
CaSO4 · 2 H2O → CaSO4 · 1/2 H2O + 1+1/2 H2O↑ The endothermic property of this reaction is relevant to the performance of drywall, conferring fire resistance to residential and other structures. In a fire, the structure behind a sheet of drywall will remain relatively cool as water is lost from the gypsum, thus preventing (or substantially retarding) damage to the framing (through combustion of wood members or loss of strength of steel at high temperatures) and consequent structural collapse. But at higher temperatures, calcium sulfate will release oxygen and act as an oxidizing agent. This property is used in aluminothermy. In contrast to most minerals, which when rehydrated simply form liquid or semi-liquid pastes, or remain powdery, calcined gypsum has an unusual property: when mixed with water at normal (ambient) temperatures, it quickly reverts chemically to the preferred dihydrate form, while physically "setting" to form a rigid and relatively strong gypsum crystal lattice:
Sources: en.wikipedia.org
Octopuses appear in mythology as sea monsters such as the kraken of Norway and the Akkorokamui of the Ainu, and possibly the Gorgons of ancient Greece. A battle with an octopus appears in Victor Hugo's book Toilers of the Sea. Octopuses appear in Japanese shunga erotic art. They are eaten and considered a delicacy by humans in many parts of the world, especially the Mediterranean and Asia.
== Living cells == According to some opinions, living eukaryotic cells perform isoelectric focusing of proteins in their interior to overcome a limitation of the rate of metabolic reaction by diffusion of enzymes and their reactants, and to regulate the rate of particular biochemical processes. By concentrating the enzymes of particular metabolic pathways into distinct and small regions of its interior, the cell can increase the rate of particular biochemical pathways by several orders of magnitude. By modification of the isoelectric point (pI) of molecules of an enzyme by, e.g., phosphorylation or dephosphorylation, the cell can transfer molecules of the enzyme between different parts of its interior, to switch on or switch off particular biochemical processes.
=== SELDI-TOF-MS === Samples spotted on a SELDI surface are typically analyzed using time-of-flight mass spectrometry. An irradiating laser ionizes peptides from crystals of the sample/matrix mixture. The matrix absorbs the energy of the laser pulse, preventing destruction of the molecule, and transfers charge to the sample molecules, forming ions. The ions are then briefly accelerated through an electric potential and travel down a field-free flight tube where they are separated by their velocity differences. The mass-to-charge ratio of each ion can be determined from the length of the tube, the kinetic energy given to ions by the electric field, and the velocity of the ions in the tube. The velocity of the ions is inversely proportional to the square root of the mass-to-charge ratio of the ion; ions with low mass-to-charge ratios are detected earlier than ions with high mass-to-charge ratios.
Formylation of benzene rings can be achieved via the Gattermann reaction and Gattermann-Koch reaction. These involve strong acid catalysis and proceed in a manner similar to the Friedel–Crafts reaction.
Diethylaminoethyl cellulose (DEAE-C) is a positively charged resin used in ion-exchange chromatography, a type of column chromatography, for the separation and purification of proteins and nucleic acids. Gel matrix beads are derivatized with diethylaminoethanol (DEAE) and lock negatively charged proteins or nucleic acids into the matrix. The proteins are released from the resin by increasing the salt concentration of the solvent or changing the pH of the solution as to change the charge on the protein.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, containing seven amino acids with a lactam ring and a D-configured phenylalanine residue. It is supplied as a lyophilised powder for laboratory research.
The natural hormone is a linear tridecapeptide that is rapidly degraded in circulation. Melanotan-2 is shortened, cyclised, N-terminally acetylated, and carries a D-amino acid substitution, all of which slow enzymatic breakdown.
No national medicines regulator has approved melanotan-2 for therapeutic or cosmetic use. In several jurisdictions it is treated as an unapproved prescription medicine, and its legal classification differs from country to country.
No regulatory agency has authorised melanotan-2 as a medicine for any indication. It circulates mainly as a research chemical or through unregulated channels. As a result, identity, purity and content are not independently guaranteed.